The operation and maintenance of oil burner units are well known. An oil burner unit typically includes a motor and an oil pump which are mounted directly opposite each other on the exterior of the oil burner unit housing. A drive coupling couples the motor shaft and the oil pump shaft so that the motor shaft drives the oil pump shaft. The motor shaft includes a flat portion ("flat") which rotates the drive coupling.
The drive coupling, which is usually made of a plastic, is comprised of a first coupling end fitting that is disposed on the oil pump shaft, a second coupling end fitting that is disposed on the motor shaft, and a connector which connects the first and second coupling end fittings.
During maintenance of the oil burner unit, it is often necessary to remove the oil pump from the oil burner unit. When the technician pulls the oil pump from the oil burner unit, the drive coupling often splits into its components with the second drive coupling end fitting remaining disposed on the motor shaft. This happens because over a period of time the plastic of the second drive coupling end fitting bonds to the metal of the motor shaft and the plastic of the first drive coupling end fitting bonds to the metal of the pump shaft. In order to reinstall the drive coupling, or replace if broken, it is necessary to remove the second drive coupling end fitting from the motor shaft.
The pump opening in the oil burner unit housing is too small to allow a technician to insert his hand or a pliers to remove the second drive coupling end fitting from the motor shaft. The common practice is to pry the second drive coupling end fitting from the motor shaft by placing a screwdriver between oil burner fan blades and prying the second drive coupling end fitting from the motor shaft. This is often a hit and miss process and there is always a risk of damaging the fan blades. Further, even if the technician removes the second drive coupling end fitting from the motor shaft by this method, the fitting invariably falls inside the housing where it is difficult to reach.
In some oil burner units, there is no access for a screwdriver to the second drive coupling end fitting between the fan blades, either because the fan blades are located so close to each other or because burner design does not allow access to the second drive coupling end fitting. In these cases, the technician must remove the motor from the oil burner unit to remove the second drive coupling end fitting, which is time consuming and laborious. If the work is performed on a mobile home furnace, the technician must remove the whole oil burner unit from the furnace to have enough room to remove the motor, wherein such removal includes disassembly. The oil burner unit disassembly tends to destroy certain burner parts and is further time consuming.